An organic light-emitting device (organic electroluminescence device or organic EL device) is an electronic device including a pair of electrodes and an organic compound layer placed between the pair of electrodes. An electron and a hole are injected from the pair of electrodes, and then the electron and the hole recombine in the organic compound layer to produce an exciton of a luminous organic compound. The organic light-emitting device emits light upon return of the exciton to its ground state.
Recent development of the organic light-emitting devices is significant and the developed devices have, for example, the following features. The light-emitting devices can be driven at low voltages, emit light beams having various wavelengths, have high-speed responsiveness, and can be reduced in thickness and weight.
By the way, creation of a compound suitable for the organic light-emitting device has been vigorously performed heretofore. This is because creation of a compound having an excellent device lifetime characteristic is important for providing a high-performance organic light-emitting device.
For example, an iridium complex having a red light-emitting arylnaphtho[2,1-f]isoquinoline as a ligand is known as a phosphorous light-emitting material having a high emission quantum yield. In Patent Literature 1, as the iridium complex having an arylnaphtho[2,1-f]isoquinoline ligand, there is a disclosure of Compound E2 shown below.

In addition, another example of the metal complex to be used as a constituent material for the organic light-emitting device is such a metal complex as disclosed in Patent Literature 2. Meanwhile, a metal complex disclosed in Patent Literature 3 or Patent Literature 4 is available as a metal complex to be incorporated as a host into an emission layer together with the iridium complex.